1. Field of the Invention
The present invention relates to a signal transmission circuit and to an electronic device, a cable, and a connector comprising the signal transmission circuit.
2. Related Background Art
The differential transmission system is one of systems for transmitting digital signals between electronic devices. The differential transmission system is a system of feeding mutually opposite digital signals on a pair of lines, and the differential transmission cancels out radiated noise from signal lines, and external noise. The cancellation of external noise results in decrease in noise, which permits transmission of signals in small amplitude. Furthermore, the signals in small amplitude offer an advantage of reduction in rise and fall times of signals, which implements increase in speed of signal transmission.
The interface standards using this differential transmission system include USB (Universal Serial Bus), IEEE1394, LVDS (Low Voltage Differential Signaling), DVI (Digital Video Interface), HDMI (High-Definition Multimedia Interface), and so on. Among these, HDMI is an interface enabling transmission of more digital signals, and high-speed interface enabling transmission of uncompressed digital signals between a source device (e.g., a DVD player, a set-top box, or the like) and a sink device (e.g., a digital television set, a projector, or the like). The HDMI permits high-speed transmission of video signals and sound signals through a single cable.
Incidentally, the increase of transmission speed leads to generation of noise even with microscopic deviation of differential signals between signal lines. A solution to this problem is a proposal on a transmission circuit that reduces the noise by insertion of a common mode choke coil in an interface such as a cable (e.g., reference is made to Japanese Patent Application Laid-Open No. 2001-85118).